This invention relates generally to a tool for mounting a safety device on high voltage electrical equipment. Specifically, the present invention relates to a tool for installing an anti-flashover ring that fits on an electrical accessory product. More particularly, the present invention relates to an installation tool that allows installation of the anti-flashover ring at a safe distance from the high voltage electrical equipment whether energized or de-energized.
As discussed in co-pending U.S. application Ser. No. 09/085,801, entitled xe2x80x9cAnti-Flashover Ring For A Bushing Insertxe2x80x9d and assigned to the Assignee of the present application, which is incorporated herein by reference, there is a need to eliminate electrical arcing during disconnection of a live source of power. As discussed therein, an anti-flashover ring for an accessory product such as a bushing insert was developed to significantly reduce this risk.
Electrical accessory products such as bushing inserts, which are typically rated for 15 kV, 25 kV, or 35 kV, are all dimensionally sized according to ANSI/IEEE Standard 386. This standard defines the various dimensional and electrical operating aspects of the electrical accessory products so that products from different manufacturers may be interchangeable. Even with these standards, it will be appreciated that there are slight dimensional variations between accessory products from different manufacturers.
There are several ways in which the anti-flashover ring can be installed on a bushing insert. The easiest way to install the ring is to place it on the bushing insert before the bushing insert is installed on high voltage electrical equipment such as a transformer. However, it will be appreciated that there are many such bushing inserts and other related accessory products already installed in the field. In order to install the anti-flashover ring onto these installed bushing inserts and the like, safe operating practice requires that all downstream equipment be de-energized. Next, the bushing insert may be removed from the transformer and the anti-flashover ring is installed on the bushing insert by hand. The bushing insert is then reinstalled and the downstream equipment is re-energized. As will be appreciated by those skilled in the art, this is a very expensive and time-consuming process and one not favored by public utility companies. Alternatively, the anti-flashover ring could be installed without removing the bushing insert from the high voltage equipment, but this is considered a dangerous option and safety practices of public utilities generally prevent this option. In order to implement this option, an operator would be required to hand install the anti-flashover ring directly onto the connected bushing insert. Hand installation is also undesirable because the dimensional variations of the bushing inserts may require special care by the installer to ensure that the ring is uniformly and properly mounted to the bushing insert.
It is thus desired in the art to provide a tool which may be adaptable for operation or use by a xe2x80x9chot stickxe2x80x9d or insulated operation tool. Furthermore, it is desired that the tool and its method for use ensure that the anti-flashover ring is properly installed onto the accessory product in an efficient and secure manner.
In light of the foregoing, it is a first aspect of the present invention to provide an anti-flashover ring installation tool and method for using the same.
Another aspect of the present invention is to provide an anti-flashover ring installation tool that maybe used with an insulated hot stick to allow safe and proper installation of the ring.
Yet another aspect of the present invention is to provide an installation tool, as set forth above, which provides alignment features prior to installing the ring onto an accessory product such as a bushing insert.
Still another aspect of the present invention is to provide an installation tool, as set forth above, that includes a housing with a spring-biased plunger assembly that positions the ring onto the bushing insert and then presses the ring onto the bushing insert.
Still yet another aspect of the present invention, as set forth above, is to provide the plunger assembly with an insert cavity having a coaxially extending rod that is received by the bushing insert during installation.
A further aspect of the present invention is to provide an installation tool, as set forth above, in which the plunger assembly includes a spring-biased holding collar which frictionally carries the ring and wherein the holding collar is slidably moveable within the plunger assembly.
Still a further aspect of the present invention is to provide an installation tool, as set forth above, wherein the holding collar contacts a surface of the bushing insert and is pushed back while a plunger in the plunger assembly positions the ring onto a shoulder of the bushing insert.
An additional aspect of the present invention is to provide an installation tool, as set forth above, in which the housing provides a final push of the anti-flashover ring until seated and frictionally held by the bushing insert.
The foregoing and other aspects of the present invention, which shall become apparent as the detailed description proceeds, are achieved by a tool for installing a ring onto a cylindrical device, comprising a housing having an inner wall with an extending edge, the inner wall defining an opening, a plunger assembly slidably coupled to the housing, the plunger assembly carrying the ring wherein the cylindrical device is received in the opening and the plunger assembly positions the ring about the cylindrical device and the extending edge presses the ring onto the cylindrical device.
Other aspects of the present invention are attained by an installation tool for installing an anti-flashover ring on an electrical accessory product such as a bushing insert, the tool comprising a housing having a cap at one end and a cup at an opposite end, the cap having a hole therethrough to receive a remote operating tool, the cup having a closed end with a bore therethrough adjacent the cap, and an open end opposite the closed end, the cup having a substantially flat cup edge at the open end, a rod slidably moveable in the bore, one end of the rod slidably mounted in the cap, a plunger slidably received in the cup, the plunger having a closed end with a rod hole therethrough, the rod fixed to the rod hole, the plunger having an open end opposite the plunger closed end, the plunger open end facing the same direction as the open end of the cup, the plunger open end having an insert cavity into which the rod coaxially extends, the plunger having an interior plunger wall with a sleeve lip and a spring lip, a spring disposed between the plunger and the cup, a sleeve mounted to the sleeve lip, a holding collar slidably movable between the sleeve and the interior plunger wall and retained within the plunger, and a collar spring disposed between the holding collar and the spring lip, the holding collar frictionally receiving the ring, wherein an operator positions the installation tool such that the rod is received by the bushing insert, the holding collar aligns the ring onto a shoulder of the bushing insert, wherein the shoulder pushes the holding collar until the plunger engages the anti-flashover ring to complete positioning of the ring onto the shoulder, and wherein the shoulder and the ring slidably move the plunger until engaged by the cup edge which completely pushes the ring onto the shoulder.
Still another object of the present invention is attained by a method for installing an anti-flashover ring onto a bushing insert, wherein the ring has an outer surface and an inner surface, and a shoulder wall extending inwardly from the inner surface, the shoulder wall having a shoulder surface, and wherein the bushing insert has a frusto-conical portion with a bore therethrough, the frusto-conical portion terminating at a shoulder which extends into a shielded collar, the method comprising the steps of positioning the ring on a spring-biased plunger assembly slidably received in a cup, the plunger assembly having an insert cavity for receiving the frusto-conical portion and a rod extending substantially coaxially into the insert cavity, aligning the spring-biased plunger assembly onto the bushing insert by inserting the rod into the bore, moving the plunger assembly until the ring is positioned onto the shoulder, further moving the plunger assembly until retracted within the cup wherein the cup pushes the ring onto the shoulder, and withdrawing the cup and the plunger assembly from the insert.
These and other aspects of the present invention, as well as the advantages thereof over existing prior art forms, which will become apparent from the description to follow, are accomplished by the improvements hereinafter described and claimed.